Hypertriglyceridemia-induced acute pancreatitis in pregnancy is not a common complication. Moreover, ketoacidosis in gestational diabetes occurs rarely. Here we report a case of ketoacidosis with hypertriglyceridemia-induced pancreatitis in a patient with gestational diabetes that was successfully treated with insulin and supportive care. In this case, a 36-year-old woman (at 32 weeks' gestation) was diagnosed with gestational diabetes 4 weeks prior, but did not have well controlled blood sugar. She complained of severe epigastric pain concomitant with nausea and vomiting. Radiology and laboratory tests found hypertriglyceridemia (1,996 mg/dL), acute pancreatitis, and ketoacidosis with absence of fetal deceleration on a non-stress test. The patient's condition improved with insulin therapy and fluid replacement. To our knowledge, this is the first report of a case of ketoacidosis with hypertriglyceridemia-induced pancreatitis in a patient with gestational diabetes. (Endocrinol Metab 27:89-92, 2012)